STRUCTURE AND BONDING

Question 1

Between molecules

Answer 1

intermolecular

Question 2

Inside molecules

Answer 2

intramolecular

Question 3

bonding continuum

Answer 3

varying degrees of ionic character

Question 4

Pure covalent

Answer 4

shared pair electrons to achieve stable outer arrangement

same electronegativities - no ionic character at all

Question 5

pure covalent example

Answer 5

diatomic elements

Question 6

Polar covalent

Answer 6

One more electronegative - becomes slightly negative and other slightly positive

Question 7

Ionic Bonds

Answer 7

Uneven sharing of bonding electrons with large electronegativity difference

Usually, but not always metal and non-metal (sodium chloride)

Pulls electrons towards itself completely, gaining electric and forming negative ion, and other is positive ion

Electrostatic force of attraction between metal ion and non-metal ion.

Arranged into 3d ionic lattice of pos and neg ions

Question 8

Intermolecular bonds

Answer 8

Van der Waals

LDF
PDP
Hydrogen

Question 9

LDF

Answer 9

weakest - exists between all atoms and molecules

uneven distribution of electrons within an atom. Results in slightly neg charge and slight pos on either side of atom - temporary dipole established

opposite charges then attract each other

Question 10

How do we know LDF are between all atoms and molecules

Answer 10

Molecular elements and monatomic elements will condense forming solids if cooled to sufficiently low temperatures - shows must be attraction that is being overcome

Question 11

Strength of LDF

Answer 11

Higher the larger the atom - more electrons so more dipoles established

Question 12

Permanent dipole interactions

Answer 12

POLAR

Polar molecules display attractions between opposite charged ends of molecules

Question 13

Hydrogen bonding

Answer 13

Strongest

Specific type of permanent dipole to permanent dipole attraction that occurs when a hydrogen atom is covalently bonded to a highly electronegative element such as nitrogen, oxygen or fluorine.

Opposite charged ends attracted

Question 14

examples of hydrogen bonds in molecules

Answer 14

Water, ammonia, alcohols and alkanoic acids

Question 15

Polarity

Answer 15

A substance which contains polar covalent bonds may not be overall polar due to SHAPE

Question 16

Water polarity

Answer 16

Water molecules are polar - due to non symmetrical shape molecule is polar (neg and pos side(o- h+))

Question 17

non-symmetrical

Answer 17

polar

Question 18

symmetrical example

Answer 18

carbon tetrachloride - non polar

Question 19

Properties ionic lattice

Answer 19

High mp/bp

conduct when molten or in solution as ions free to move

Question 20

how can ionic lattice be broken down

Answer 20

electryolisis

Question 21

properties covalent network

Answer 21

v high mp/mp

hard and do not conduct

Question 22

properties covalent molecular

Answer 22

low mp/bp

do not conduct some have higher mp than expected - because of intermolecular bond present

Question 23

Ethanol 79 degrees and Ether -23 degrees- same molecular formula

Answer 23

Same molecular formula

large difference in bp

due to ethanol containing H bonding

Ether is symmetrical so even though contains polar bonds, overall non polar and only bonds present will be LDF

Question 24

Properties of water

Answer 24

due to hydrogen bonding

density of ice less - water expanding when frozen because hydrogen forming open lattice

high surface tension

relatively high viscosity

Question 25

Ionic lattice and polar covalent solubility

Answer 25

soluble in water and other polar solvents

insoluble in non-polar

Question 26

solubility rule

Answer 26

“like dissolves like”